/*
 * @(#)Naming.java	1.24 05/11/17
 *
 * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
package java.rmi;

import java.rmi.registry.*;
import java.net.MalformedURLException;
import java.net.URI;
import java.net.URISyntaxException;

/**
 * The <code>Naming</code> class provides methods for storing and obtaining
 * references to remote objects in a remote object registry.  Each method of
 * the <code>Naming</code> class takes as one of its arguments a name that
 * is a <code>java.lang.String</code> in URL format (without the
 * scheme component) of the form:
 *
 * <PRE>
 *    //host:port/name
 * </PRE>
 * 
 * <P>where <code>host</code> is the host (remote or local) where the registry
 * is located, <code>port</code> is the port number on which the registry
 * accepts calls, and where <code>name</code> is a simple string uninterpreted
 * by the registry. Both <code>host</code> and <code>port</code> are optional.
 * If <code>host</code> is omitted, the host defaults to the local host. If
 * <code>port</code> is omitted, then the port defaults to 1099, the
 * "well-known" port that RMI's registry, <code>rmiregistry</code>, uses.
 *
 * <P><em>Binding</em> a name for a remote object is associating or
 * registering a name for a remote object that can be used at a later time to
 * look up that remote object.  A remote object can be associated with a name
 * using the <code>Naming</code> class's <code>bind</code> or
 * <code>rebind</code> methods.
 *
 * <P>Once a remote object is registered (bound) with the RMI registry on the
 * local host, callers on a remote (or local) host can lookup the remote
 * object by name, obtain its reference, and then invoke remote methods on the
 * object.  A registry may be shared by all servers running on a host or an
 * individual server process may create and use its own registry if desired
 * (see <code>java.rmi.registry.LocateRegistry.createRegistry</code> method
 * for details).
 *
 * @version 1.13, 09/05/99
 * @author  Ann Wollrath
 * @author  Roger Riggs
 * @since   JDK1.1
 * @see     java.rmi.registry.Registry
 * @see     java.rmi.registry.LocateRegistry
 * @see     java.rmi.registry.LocateRegistry#createRegistry(int)
 */
public final class Naming {
    /**
     * Disallow anyone from creating one of these
     */
    private Naming() {}

    /**
     * Returns a reference, a stub, for the remote object associated
     * with the specified <code>name</code>.
     *
     * @param name a name in URL format (without the scheme component) 
     * @return a reference for a remote object
     * @exception NotBoundException if name is not currently bound
     * @exception RemoteException if registry could not be contacted
     * @exception AccessException if this operation is not permitted
     * @exception MalformedURLException if the name is not an appropriately
     *  formatted URL
     * @since JDK1.1
     */
    public static Remote lookup(String name)
	throws NotBoundException,
	    java.net.MalformedURLException,
	    RemoteException
    {
	ParsedNamingURL parsed = parseURL(name);
	Registry registry = getRegistry(parsed);

	if (parsed.name == null)
	    return registry;
	return registry.lookup(parsed.name);
    }

    /**
     * Binds the specified <code>name</code> to a remote object.
     *
     * @param name a name in URL format (without the scheme component) 
     * @param obj a reference for the remote object (usually a stub)
     * @exception AlreadyBoundException if name is already bound
     * @exception MalformedURLException if the name is not an appropriately
     *  formatted URL
     * @exception RemoteException if registry could not be contacted
     * @exception AccessException if this operation is not permitted (if
     * originating from a non-local host, for example)
     * @since JDK1.1
     */
    public static void bind(String name, Remote obj)
	throws AlreadyBoundException,
	    java.net.MalformedURLException,
	    RemoteException
    {
	ParsedNamingURL parsed = parseURL(name);
	Registry registry = getRegistry(parsed);

	if (obj == null)
	    throw new NullPointerException("cannot bind to null");

	registry.bind(parsed.name, obj);
    }

    /**
     * Destroys the binding for the specified name that is associated
     * with a remote object.
     *
     * @param name a name in URL format (without the scheme component) 
     * @exception NotBoundException if name is not currently bound
     * @exception MalformedURLException if the name is not an appropriately
     *  formatted URL
     * @exception RemoteException if registry could not be contacted
     * @exception AccessException if this operation is not permitted (if
     * originating from a non-local host, for example)
     * @since JDK1.1
     */
    public static void unbind(String name)
	throws RemoteException,
	    NotBoundException,
	    java.net.MalformedURLException
    {
	ParsedNamingURL parsed = parseURL(name);
	Registry registry = getRegistry(parsed);

	registry.unbind(parsed.name);
    }

    /** 
     * Rebinds the specified name to a new remote object. Any existing
     * binding for the name is replaced.
     *
     * @param name a name in URL format (without the scheme component)
     * @param obj new remote object to associate with the name
     * @exception MalformedURLException if the name is not an appropriately
     *  formatted URL
     * @exception RemoteException if registry could not be contacted
     * @exception AccessException if this operation is not permitted (if
     * originating from a non-local host, for example)
     * @since JDK1.1
     */
    public static void rebind(String name, Remote obj)
	throws RemoteException, java.net.MalformedURLException
    {
	ParsedNamingURL parsed = parseURL(name);
	Registry registry = getRegistry(parsed);

	if (obj == null)
	    throw new NullPointerException("cannot bind to null");

	registry.rebind(parsed.name, obj);
    }

    /**
     * Returns an array of the names bound in the registry.  The names are
     * URL-formatted (without the scheme component) strings. The array contains
     * a snapshot of the names present in the registry at the time of the
     * call.
     *
     * @param 	name a registry name in URL format (without the scheme
     *		component)
     * @return 	an array of names (in the appropriate format) bound
     * 		in the registry
     * @exception MalformedURLException if the name is not an appropriately
     *  formatted URL
     * @exception RemoteException if registry could not be contacted.
     * @since JDK1.1
     */
    public static String[] list(String name)
	throws RemoteException, java.net.MalformedURLException
    {
	ParsedNamingURL parsed = parseURL(name);
	Registry registry = getRegistry(parsed);

	String prefix = "";
 	if (parsed.port > 0 || !parsed.host.equals(""))
	    prefix += "//" + parsed.host;
	if (parsed.port > 0)
	    prefix += ":" + parsed.port;
	prefix += "/";

	String[] names = registry.list();
	for (int i = 0; i < names.length; i++) {
	    names[i] = prefix + names[i];
	}
	return names;
    }

    /**
     * Returns a registry reference obtained from information in the URL.
     */
    private static Registry getRegistry(ParsedNamingURL parsed)
	throws RemoteException
    {
	return LocateRegistry.getRegistry(parsed.host, parsed.port);
    }

    /**
     * Dissect Naming URL strings to obtain referenced host, port and
     * object name.
     *
     * @return an object which contains each of the above
     * components.
     *
     * @exception MalformedURLException if given url string is malformed
     */
    private static ParsedNamingURL parseURL(String str) 
	throws MalformedURLException 
    {
	try {
	    return intParseURL(str);
	} catch (URISyntaxException ex) {
	    /* With RFC 3986 URI handling, 'rmi://:<port>' and
	     * '//:<port>' forms will result in a URI syntax exception
	     * Convert the authority to a localhost:<port> form
	     */
	    MalformedURLException mue = new MalformedURLException(
		"invalid URL String: " + str);
	    mue.initCause(ex);
	    int indexSchemeEnd = str.indexOf(':');
	    int indexAuthorityBegin = str.indexOf("__JOT_PIECE_14__
	    if (indexAuthorityBegin <__JOT_PIECE_47__) {
		throw mue;
	    }
	    if ((indexAuthorityBegin == 0) ||
		    ((indexSchemeEnd > 0) &&
		    (indexAuthorityBegin == indexSchemeEnd + 1))) {
		int indexHostBegin = indexAuthorityBegin + 2;
		String newStr = str.substring(0, indexHostBegin) +
				"localhost" +
				str.substring(indexHostBegin);
		try {
		    return intParseURL(newStr);
		} catch (URISyntaxException inte) {
		    throw mue;
		} catch (MalformedURLException inte) {
		    throw inte;
		}
	    }
	    throw mue;
	}
    }
    
    private static ParsedNamingURL intParseURL(String str)
	throws MalformedURLException, URISyntaxException
    {
	URI uri = new URI(str);
	if (uri.isOpaque()) {
	    throw new MalformedURLException(
		"not a hierarchical URL: " + str);
	}
	if (uri.getFragment() != null) {
	    throw new MalformedURLException(
		"invalid character, '#', in URL name: " + str);
	} else if (uri.getQuery() != null) {
	    throw new MalformedURLException(
		"invalid character, '?', in URL name: " + str);
	} else if (uri.getUserInfo() != null) {
	    throw new MalformedURLException(
		"invalid character, '@', in URL host: " + str);
	}
	String scheme = uri.getScheme();
	if (scheme != null && !scheme.equals("rmi")) {
	    throw new MalformedURLException("invalid URL scheme: " + str);
	}

	String name = uri.getPath();
	if (name != null) {
	    if (name.startsWith("/")) {
		name = name.substring(1);
	    }
	    if (name.length() == 0) {
		name = null;
	    }
	}

	String host = uri.getHost();
	if (host == null) {
	    host = "";
	    try {
		/*
		 * With 2396 URI handling, forms such as 'rmi://host:bar'
		 * or 'rmi://:<port>' are parsed into a registry based
		 * authority. We only want to allow server based naming
		 * authorities.
		 */
		uri.parseServerAuthority();
	    } catch (URISyntaxException use) {
		// Check if the authority is of form ':<port>'
		String authority = uri.getAuthority();
		if (authority != null && authority.startsWith(":")) {
		    // Convert the authority to 'localhost:<port>' form
		    authority = "localhost" + authority;
		    try {
			uri = new URI(null, authority, null, null, null);
			// Make sure it now parses to a valid server based
			// naming authority
			uri.parseServerAuthority();
		    } catch (URISyntaxException use2) {
			throw new
			    MalformedURLException("invalid authority: " + str);
		    }
		} else {
		    throw new
			MalformedURLException("invalid authority: " + str);
		}
	    }
	}
	int port = uri.getPort();
	if (port == -1) {
	    port = Registry.REGISTRY_PORT;
	}
	return new ParsedNamingURL(host, port, name);
    }
    
    /**
     * Simple class to enable multiple URL return values.
     */
    private static class ParsedNamingURL {
	String host;
	int port;
	String name;
	
	ParsedNamingURL(String host, int port, String name) {
	    this.host = host;
	    this.port = port;
	    this.name = name;
	}
    }
}